I. Field of the Invention
Portable hydraulic log splitters are increasingly being desired by experienced outdoorsmen, wood gatherers, and campers. Portable hydraulic log splitters greatly reduce the amount of time and effort needed to split wood or logs into manageable pieces for consumption.
Efforts to develop hydraulic log splitters generally available to the public have resulted in a variety of cumbersome integrated devices that, only in theory, are portable. Portable hydraulic log splitters that are currently available are wedded to one particular form of propulsion or another and include relatively heavy structural members. Also, these log splitters involve very complex machinery that is prone to breakdown. Finally, some log splitters are potentially dangerous tools that are often used on camping trips and other forays away from public assistance without the availability of an automatic safety or failsafe switch. Thus, there is a need for a portable hydraulic log splitter that operates in a simple fashion, can be broken down into components having manageable weights for ease of transportation and use, and that can be operated safely.
The invention relates to a portable hydraulic log splitter that can be broken down into components and is adaptable to operate with either an electric or gas motor. The embodiments disclosed are actuated through the operation of a single stage hydraulic pump and a four position regenerative safety release valve. The pump can be powered through the use of either a gas or an electric motor. The splitter further offers safety features through the use of a control valve that is biased towards automatic disengagement of driving force applied to the cutting blade. The disclosed invention also includes a selection of splitting speeds and further includes various novel arrangements to reduce the weight of the modular assembly.
II. Description of the Prior Art
U.S. Pat. No. 4,498,293 (Gregory) discloses a portable hydraulic log splitter where a pusher member carried on a cylinder pushes a log against a blade carried on a frame to which the cylinder is secured. Gregory discloses an electric motor to power the log splitter that is mounted to the log splitter frame. Gregory is directed towards a hydraulic actuator pump based upon a ball and cup system that blocks off certain passageways to build up pressure within the pump to overcome log resistance.
Gregory does not suggest the desirability of a separable power pack for a log splitter module, nor does he suggest the possibility of a pump that can be powered by either electric or gas motors. Likewise, Gregory does not disclose any safety features for the automatic disengagement of the splitting/retraction driving forces applied to the cutting blade. Also, Gregory discloses a structure for pushing a log toward a stationary blade, thus providing a more unwieldy means of splitting wood than the present invention. Further, Gregory does not disclose the feature of having a user selectable overdrive capability for increasing cutting speed.
U.S. Pat. No. 4,782,870 (Duerr '870) discloses a portable wood splitter having a splitter frame adjustably mounted to a support frame. Duerr '870 suggests the desirability of rotating a log splitter for splitting operation in either a vertical or horizontal position. Duerr further discloses a towing tongue and a hitch connector for connection to a car or some other similar form of motorized transport.
Duerr '870, however, does not disclose or suggest the desirability of a separate, modular power pack. Further, while Duerr '870 does disclose the use of a stripper, it offers no safety feature that guarantees the automatic disengagement of the cutting blade in combination with an optional higher splitting speed feature. Duerr '870 also does not disclose the flexibility of providing either electric or gas motor drive for a pump or a relatively lightweight log cutting support frame.
U.S. Pat. No. 4,770,218 (Duerr '218) discloses a portable log splitter with a block stripper and stroke stop. Duerr '218 discloses a collar-type attachment that can be selectively positioned along a frame to abut the cutting blade as it is withdrawn from its fully extended position. Duerr '218, however, is directed toward the efficiency in the cutting action of the machine, not the user safety features of the blade stroke. Further, Duerr '218 does not suggest a separable power pack unit for driving the log splitter.
In short, none of the prior art, alone or in combination suggest a modular hydraulic log splitter with an automatic safety disengage feature in combination with an optional high speed splitting mode. Further, none of the prior art discloses a portable hydraulic log splitter with a detachable power pack that can be powered by either a gas or electric motor, in combination with a control valve that is biased toward a "power off" or neutral condition. And no suggestion is made for a relatively lightweight support frame including a cutting blade of hardened tool steel compositely and integrally molded into an aluminum mounting and transport base.